<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>key的原理</title>
  <!-- 引入Vue -->
  <script type="text/javascript" src="../js/vue.js"></script>
</head>

<body>
  <!-- 准备好一个容器 -->
  <div id="root">
    <!-- 遍历数组 -->
    <h2>人员列表</h2>
    <button @click.once="add">添加一个老刘</button>
    <ul>
      <li v-for="(p,index) in persons" :key="p.id">
        {{p.name}}--{{p.age}}
        <input type="text">
      </li>
    </ul>

  </div>
</body>

<script type="text/javascript">

  new Vue({
    el: '#root',
    data: {
      persons: [
        { id: '001', name: '张三', age: '18' },
        { id: '002', name: '李四', age: '19' },
        { id: '003', name: '王五', age: '20' },
      ],
    },
    methods: {
      add() {
        const p = { id: '004', name: '老刘', age: '40' }
        this.persons.unshift(p)
      }
    },
  })
</script>

</html>